1. Field of the Invention
The invention is a process for producing stable asphalt emulsions. The emulsions comprise asphalt particles, water and an ethylene oxide/propylene oxide/ethylene oxide block copolymer emulsifying agent.
2. Description of Related Methods in the Field
Crude petroleum is refined to produce fuel and lubricating products. Petroleum may be supplemented with much lesser amounts of other crude oils from bituminous sand and shale. These crude oils require greater or lesser amounts of refining to convert them to products. Their individual properties are determined by the sum of the components.
Crude oils with greater amounts of asphalt, metals, organic sulfur and organic nitrogen require additional processing to remove them. Asphalt is a mixture of asphaltene and maltene. Of these constituents, asphalt is removed relatively earlier in the refining process because it interferes with processes such as hydrotreating to remove organic sulfur and nitrogen. In particular, asphalt produces amounts of coke which deactivates hydrotreating catalyst. It also forms precipitates and contains precipitate precursors which hinder subsequent processing.
In the past, asphalt and heavier components of crude oil were either used in road paving or added to bunker fuels and combusted. Recently, because of the Clean Air Act, the emission regulations have become more stringent in NO.sub.x and sulfur emissions therefore, creating a need to use up asphalt by other means.
U.S. Pat. No. 5,000,757 to S. J. Puttock et al. discloses the preparation and combustion of fuel oil emulsions.
U.S. Pat. No. 5,089,052 to A. C. Ludwig discloses the emulsification of rock asphalt. The emulsions are formulated to be effective as binders for limestone aggregate coatings, seals, coats, pliable mats and other applications.
U.S. Pat. No. 4,776,977 to S. E. Taylor discloses emulsions of oil in water. These emulsions are noted for the relatively high proportion of discontinuous phase. The emulsions are suitable for pipeline transportation.
U.S. Pat. No. 4,978,365 to A. A. Gregoli et al. discloses the preparation of crude oil emulsions for pipeline transmission. The emulsifying agent is an ethoxylated alkylphenol. Linear alkyl moieties may be attached to the alkylphenol.
There is a need in the art for a commercial process which uses solid asphalt from crude oil refining and from solvent deasphalting processes.